Process of precipitating viscose



FRANZ STETMMTG, 01F HANOVER, GERNT.

PRU'CESS T PRECTPTTAG VISCOSE.

teaser.

Specification of Letters Patent.

Patented Dec. 0, ffidf.

lt'o Drawing. tlrtginal application filed June it, 1913, serial No.773,32t. Divider]. and this application filed August 112, 1916 ficrial llo. 114L661.

(GRANTED UNDER THE JPRO VIEIMIDNS 01E THE ACT 0T lltlflR'Ull-l 3, 1921,M STAT. L, 1313.)

To all whom it may concern:

- Hanover, Germany, have invented certain new and useful Improvements inProcesses of' Precipitating Viscose, (for which T have filedapplications in Germany, Feb. 15, 1913,

flit lift L which is produced viscose.

and Great Britain May 10, 1913,) of which the following is aspecification.

This invention relates to the production of cellulose compounds suitablefor use as films or filaments for fabrics from the material knowncommercially as viscose from a solution of cellu-- lose as described inT]. S. Patent No. 520770 dated June 5th, 1894.

lln the manufacture of threads suitable.

for the manufacture of yarns and fabrics from viscose, preference hasbeen given to setting baths consisting of acidulated solutions. This isreadily understood in view of the fact that viscose contains a cellulosederivative which is soluble in an alkaline solution, that is to say, itcannot be precipitated by being acted upon by an alkali.

Nevertheless it would be, advantageous to employ a setting bath with analkaline action for cellulose derivatives produced from ft is known thatviscose may be coagulated by the aid of a concentrated solution of aneutral salt, (Patent .No, 520770 of 189i.) This coagulating actioncannot, however, be employed commercially in a satisfactory manner toproduce, derivatives. of cellulose with continuous operation of theprocess owing}; to the fact that the increasing quantity of alkaliin-the bath soon renders its presence felt by preventing the cosomewhatunexpected as in'view of the experience gained with the processdescribed in T]. S. Patent No. 622087 dated 28th March, 1899, it wouldappear that only a' concentrated solution (say to 40%) of ammoniumsulfate would provide an ef-' bered that it is impossible with ordinarycommercial, viscose to precipitate a single filament with a ten percent.ordinary solut on of ammonium sulfate.

Tn making the setting bath, T preferably prepare a solution containingammonium sulfate, and a neutral salt such as sodium sulfate (Glauberssalt), magnesium chlorid, calcium-ohlorid, or sodium chlorid. Tn placeof such neutralsalts, T can also employ such a material as a tertiaryalcohol, e. g. glycerin.

The quantity of ammonium salt to be added to the neutral salt solutionsuch as brine may be varied within narrow limits only. The amountdepends to a great extent u on the kind of product which it is desire toproduce and would require to be diflerent in the case of coarse fibers,say imitation horse hair and in the case of fine fibers such as arenecessary. for artificial silk. The bestmy improved precipitating bathsome third I substance, (such as an oxidizing agent or a reducing salt)just as in the case of acid baths. These agents, which may be sugar,arsenous compounds or the like, (which act as reducing agents) or sodiumhypochlorite (which acts as an oxidizing agent) have the effect ofadding brilliancy to the fibers. It is also quite practical to add metalsalts to the precipitating bath as is known in another process, whichsalts form insoluble sulfids with the alkaline sulfid. This lattermethod is not however necessary as experience shows that with the hereindescribed new bath there is no tendency of the fibers to become sticky.

The filaments or films may he squirted in any suitable way into theprecipitating bath and on leaving this they are wound prefer.

ably on a drum which rotates in brine. in. this way the cellulosederivatives are washed,

. organic substances are'added for known purposes to affect the productand it has been found that with the invention such substances may beused with similar results as obtained in the known coagulatingsolutions.

In all cases I prefer to employ a setting bath containing one or more ofthe neutral salts above referred to (NaCl, Na SO MgCl CaCl etc.), whichcompounds are generically referred to as a neutral salt of analkali-forming metal and also containing a relatively small amount of anammonium salt, capable of existing in solution with the neutral salt(one or more of such) employed. Other agents for the productlon ofspecial effects may be added if desired. The bath will preferably besubstantially saturated with the neutral salt employed.

I call particular attention to the use of a solution made up bydissolving in thirty parts of water, sixty parts of Glaubers salt (Na SO10H O) and ten parts of ammoniumesulfate. Such a bath has givenexcellent results, and is preferably maintained at a temperature of 35to C.

Another bath which I find givesexcellent results is a solutioncontaining 19 parts Nacl 12.5 pants Cacl 10 parts NH |Cl,

and 48.5 parts water. Another bath giving excellent results is asolution of 45 parts CaCl 10 parts NH Cl; and 45 parts of water.Magnesium chlorid in various mixtures gives good results.

Regarding the ammonium salt, this may be ammonium sulfay 'or ammoniumchlorid, and I find that a mixture of these two, also gives goodresults.

I do not claim the setting baths, per se, in the present case, sincesaid baths form the subject matter of -my copending application 773,324of which the present case is a division.

What I claim is 1. Process for treating cellulose products for themanufacture of films and filaments, which consistsin squirting theviscose into an acid-free concentrated solution of a neutral salt alsocontaining only a small percentage of an ammonium salt.

2. A process of treating viscose which comprises subjecting the same tothe action of an acid-free bath containing a neutral salt and about tenper cent. of ammonium sulfate.

'sulfate and containing a small 3. Aprocess of treating viscose whichconsists in squirting the same into an acidfree solution containingammonium sulfate and sodium sulfate.

4. A process for treating viscose which comprises subjecting the same tothe action of an acid-free setting bath comprising asolution-substantially saturated with a neutral salt, and containing asmall percentage only of an ammonium salt.

5. A process of treating viscose which comprising subjecting the same tothe action'of an acid-free setting bath comprising a solutionsubstantially saturated with a neutral salt, and containing not over 10%of an ammonium salt.

6. A process of treating viscose which comprises subjecting the same tothe action of an acid-free setting bath comprising a solutionsubstantially saturated with a neutral salt, and containing not over 10%of ammonium sulfate.

7. A process of treating viscose which comprises subjecting the same tothe action of an acid-free setting bath comprising a. solutionsubstantially saturated with sodium percentage only of an ammonium salt.

8. A process of treating viscose which comprises subjecting the same tothe action of an acid-free setting bath comprising a solutionsubstantially saturated with sodium sufate and containing not over 10%of an ammonium salt.

9. A process of treating viscose whichcomprises subjecting the same tothe action of an acid-free settin bath comprisin a solutionsubstantially saturated with sodium sulfate and containing not over 10%of an ammonium sulfate.

10. A process of treating viscose which comprises subjecting the same tothe action of an acid-free setting bath comprisin a solutionsubstantially saturated with sodium sulfate and containing an ammoniumsalt.

11. A process of treating viscose which comprises subjecting the same tothe action of an acid-free setting bath comprising a solutionsubstantially saturated with a nontral salt of an alkali forming metaland COiltiLlIllIlg not over 10% of an ammonium sa t.-

12. A process of treating viscose which comprises subjecting thesame tothe action of an acid-free setting bath comprising a solutionsubstantially saturated with a neutral salt ofan alkali forming metaland containing a small percentage of an ammonium salt.

13. A process of treating viscose which comprises subjecting the same tothe action of an acid-free setting bath comprising a solutionsubstantially saturated with a neutral salt of an alkali forming metaland containing ammonium sulfate.

meats? 14L A process of treating viscose which comprises subjecting thesame to the action of an acid-free setting bath comprising a solutionsubstantially saturated with sodium sulfate and containing a smallpercentage of ammonium sulfate.

15. A process of treating viscose which comprises subjecting the same tothe action of an acid-free setting bath comprising a solutionsubstantially saturated with sodium 10 sulfate and containing not over10% of an ammonium sulfate.

In testimony whereof ll afiix my signature in the presence of twoWitnesses.

- FRANZ STEIMMIG. Witnesses:

N. N. BEHNE, R. MICHAELS.

